Dielectric Modulated Biosensor Architecture: Tunneling or Accumulation Based Transistor?

Abstract

In this paper, we present a feasibility assessment of tunneling and accumulation mode p-type transistor architectures for use as dielectric-modulated biosensors. The performance of devices is compared through the estimation of the change in electrical characteristics between Iris antigen (bioreceptor) and anti-Iris antigen (target biomolecule) for a partially filled cavity. While tunnel field-effect transistors (TFETs) achieve higher sensitivity when biomolecules are positioned at the source–channel junction, the sensitivity rapidly diminishes when biomolecules are located away from the tunneling junction and, thus, severely limits their utility. Although accumulation mode field-effect transistors (AMFETs) also exhibit location-dependent sensitivity degradation, they show higher sensitivity values in comparison to the TFET for biomolecule layer located away from the source–channel junction. Furthermore, the application of back bias (~1 V) significantly improves the sensitivity (>8) for 40% filled cavity of p-type AMFET biosensors for all locations in the dielectric cavity. As higher sensitivity values over a wider biomolecule location are desirable, an AMFET performs better in comparison to the TFET cavity-modulated biosensor. This paper presents a systematic analysis, highlighting the benefits and limitations of each device for biosensing applications. Results highlight new viewpoints and insights in the design of AMFET-based cavity-modulated biosensors.